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61 terms

Aortic Vascular surgery (TAAA, ascending and arch aneurysms))

DeBakey type I TAAA
Originates in the ascending aorta, propagates at least tot he aortic arch and often beyond it distally
DeBakey Type II TAAA
originates in and is confined to the ascending aorta
DeBakey Type III TAAA
Originates in the descending aorta and extends distally down the aorta or rarely retrograde into the aortic arch and ascending aorta
Stanford Type A TAAA
All dissections involving the ascending aorta regardless of the site of origin
Stanford Type B TAAA
All dissections not involving the ascending aorta
3 categories of thoracoabdominal disease
acute dissection
subacute dissection
stable TAAA
characteristics of acute dissections
transactions usually emergent
characteristics of subacute dissections
expending aneurysms usually urgent
characteristics of stable TAAA
may be elective surgery
usually an incidental finding
3 indications for a TAAA
greater than 6cm
growing at a rate of greater than 1cm/yr
what is a class s/s of TAAA
back pain
What are 4 areas that must be focused on the the pre-op TAAA pt.
What are considerations pre-op for the TAAA pt.
prepare for blood loss
might need DLT, deep hypothermic arrest, partial or full heart bypass, descending spinal drain
poss. mediastinal mass
What is the mortality rate for descending TAAA and dissections
What systems are most involved with TAAA complications
cardiopulmonary and renal
What approach is often used for descending TAAA
thoracotomy approach
What are 5 considerations for the TAAA patient
large blood loss
a-line on right side
Why is there are high risk for paralyzation in the TAAA patient
Because there is lack of perfusion to the spinal nerves
What are 3 surgical approaches to the open TAAA
simple clamp and sew
gott shunt
partial left-sided heart bypass
Name 3 characteristics of the simple clamp and sew method
leads to ischemia distal to the cross clamp
used for short and emergency procedures
exaggerated response to clamping and unclamping
4 characteristics of the gott shunt
proximal to distal aorta shunting
additional fem. a-line to assess perfusion
partial anti-coagulation required
partial anti-coagulation
2 characteristics of partial left-sided heart bypass
occurs if aneurysm is proximal enough to the aortic arch or aorta too calcified
full anticoagulation
What do you want to avoid during induction of the TAAA patient
minimize an increase or a precipitous drop in blood pressure
What would be the DOC for hypertensive episode during induction of the TAAA pt.
esmolol or other beta blockers
What % if patients get spinal ischemia during TAAA cross clamping above the diaphragm
What supplies anterior 2/3 of spinal cord
anterior spinal artery
What supplies the posterior 1/3 of spinal cord
posterior spinal artery
Artery of Adamkiewicz t9-t12
artery of Adamkiewicz t8-t13
artery of Adamkiewicz L1-L2
What are 4 risk factors for spinal ischemia in the TAAA patient
duration of cross clamp
presence of dissection
surgical technique
2 types of spinal ischemia
delayed onset
pt paraplegic on awakening from anesthesia that is usually irreversible
pt several hours to days after end of surgery might be reversed
delayed onset
With descending TAAA and dissections, what can be done to alleviate increase in CSF
CSF drain (lumbar drain in place)
placed if pressure exceeds 10mmHg
left in for 24hours
What is necessary to pull lumbar drain
normal coagulation studies
What are 6 complications of spinal drain complications placed for the TAAA patient
brain herniation
epidural hematoma
spinal cord injury
back pain
What are 4 drugs that have been used to help protect the spinal cord
Treatment regimen for delayed onset spinal cord ischemia
elevation of blood pressure (increase MAP)
consider CSF drainage
frequent neuro checks
Mechanical injury to the aorta is often do to what kind of trauma
deceleration injury
What is the most common site of injury to the aorta during mechanical injury
site of fixation of the aorta to the thorax known as the ligamentum arteriosum
Where is the ligamentum arteriosum located
just distal to the origin of the left subclavian artery
An endograft repair of the TAAA will be done under what kind of anesthesia
general anesthesia
Ascending aorta and arch aneurysms and dissections have similar considerations to what type of surgery and what might it involve
similar to open heart surgery
might involve aortic valve replacement and will often have aortic regurge
3 requirements for ascending aorta and arch aneurysms and dissections
will require CPB, full anticoagulation, and no cross-clamping
Of Type A and type B, which is most likely to be treated medically and which surgically?
type A - surgically
type B - medically
Most common predisposing factor for dissection
What are 3 other risk factors for dissection
marfan syndrome
ehlers danlos syndrome
deceleration injuries
Early treatment of ascending aorta and arch aneurysms and dissections
decrease blood pressure (maintain end-organ perfusion)
nicardepine, beta blockers, NTG, nipride
pain control
maintain uop
What is a patient at risk for with aortic arch surgery
high risk of stroke and ischemic brain injury due to interruption of cerebral perfusion
A 10 degree decrease in body temperature decreases cerebral metabolic rate by what
a factor of 2.6
How long can ischemic tolerance last at 15 and 10 deg. C
10 deg. C = 40 minutes
15 deg. C = 30 minutes
At what temperature would you observe an isoelectric EEG line
15deg. C
During DHCA, when does rewarming need to occur
before coming off of CPB
What is systemic hypothermia associated with?
What are 3 drugs that are often used in conjunction with DHCA?
sodium thiopental
What dosage of sodium thiopental and propofol have been used with DHCA
sodium thiopental - 2-40mg/kg
propofol - 3-10mg/kg
What vessels is used during retrograde cerebral perfusion is what is the idea behind this method?
the SVC is used. Cold oxygenated blood is delivered with idea to provide some oxygen and nutrients to the brain
pH stat is used in what population
infants and neonates
alpha stat is used in what population
pH stat used in adults have shown increased incidence of what?
cerebral embolism
(possible C02)